Largest Platypus Fossil Discovered in Australia, Rewrites History

A team of researchers has unearthed a fossilized molar belonging to a giant meat-eating platypus from a fossil site in Australia. Analysis of the newly identified species suggests that it was twice the size of the modern Monotreme (platypus).

Researchers from the University of New South Wales have unearthed a single fossilized tooth from the Riversleigh World Heritage Area of northwest Queensland, Australia. Analysis of this largest fossilized molar suggests that it belonged to an unknown extinct platypus species called 'Obdurodon tharalkooschild'. Measuring a meter long, the scientists claim that the ancient species was twice the size of the modern platypus.

Till date scientists believed that the platypus lineage was relatively linear, with just one single species inhabiting the Earth. But this new discovery proves that there existed side branches in this family tree.

The researchers say that this giant platypus is somewhere between 5 million-15 million years old. The bumps and ridges on the tooth give a good indication of the ancient species' diet.

"Monotremes (platypuses and echidnas) are the last remnants of an ancient radiation of mammals unique to the southern continents. A new platypus species, even one that is highly incomplete, is a very important aid in developing understanding about these fascinating mammals," said Rebecca Pian, PhD candidate and the lead author of the study, in a statement.

The oldest known platypus fossil was unearthed from South America. But the youngest platypus fossil was discovered in present day's Simpson Desert, Australia. Until the latest discovery of Obdurodon tharalkooschild, the fossils indicated that platypuses shrunk in size and simultaneously the size of the teeth also reduced.

The modern adult platypus doesn't have teeth but instead has horny pads in its mouth.

"Like other platypuses, it was probably a mostly aquatic mammal, and would have lived in and around the freshwater pools in the forests that covered the Riversleigh area millions of years ago," said Dr. Suzanne Hand of the University of New South Wales, co-author of the study. "Obdurodon tharalkooschild was a very large platypus with well-developed teeth, and we think it probably fed not only on crayfish and other freshwater crustaceans, but also on small vertebrates including the lungfish, frogs, and small turtles that are preserved with it in the Two Tree Site fossil deposit."

Looks like Australia is becoming a hot spot for uncovering ancient fossils. Apart from the platypus fossilized molar, earlier this month researchers discovered the footprints of Australia's ancient bird that dates back to some 100 million years.